JPH0673651B2 - Coating agent supply device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention continuously supplies a coating agent such as a paint, a dye, and an oil, which is pressure-fed from a coating agent feeding source at a predetermined pressure, to a coating machine at a constant flow rate. The present invention relates to a coating agent supply device.

[Prior art and its problems]

In a coating machine such as an air spray gun, if the flow rate of the coating material supplied to the coating machine changes, the discharge amount of the coating material sprayed from the coating machine will change, resulting in coating defects such as uneven coating. It is necessary to maintain a constant supply of paint.

For this reason, normally, for example, a pump that pumps the paint to the coating machine is driven at a constant rotation speed to keep the supply flow rate constant.

However, even if the pump is driven at a constant rotation speed, pressure loss fluctuates at the suction port and the discharge port of the pump due to the flow state of the paint, etc. could not.

Therefore, in particular, when it is necessary to maintain the paint supply flow rate constant, conventionally, a flow meter is installed in the paint supply pipe to measure the paint flow rate, and the output of the pump is controlled according to the fluctuation of the flow rate. However, since the paint has a viscosity higher than that of an ordinary liquid, it is difficult to measure accurately, and the paint adheres to the detection part of the flowmeter and is liable to malfunction.

Further, if an ultrasonic flow meter is used, the flow rate of the paint can be measured from the outside of the supply pipe in a non-contact manner, but there is a drawback that noise is easily picked up and it is expensive.

Therefore, the applicant of the present invention accurately controls the supply amount of the coating agent having high viscosity without directly measuring the flow rate, and continuously supplies the coating agent to the coating machine while maintaining the predetermined flow rate. We provided a coating material supply device that can
(See Japanese Patent No. 66).

This is to continuously apply the coating fluid at a predetermined flow rate by alternately supplying the hydraulic fluid to two reciprocating pumps that are driven by the hydraulic fluid and discharge the coating fluid at a flow rate according to the feed amount of the hydraulic fluid. Is to be supplied to.

However, subsequent experiments have revealed that when the coating agent is supplied using this apparatus, the flow of the coating agent pulsates when switching from one reciprocating pump to the other reciprocating pump.

That is, in this coating agent supply device, since the two-position piston valve is used to alternately supply the working fluid to the two reciprocating pumps, any reciprocating pump can be operated at the moment of switching the valve position. The working fluid is not supplied, and the coating agent is not discharged from any of the reciprocating pumps instantaneously, causing pulsation in the flow of the coating agent supplied to the coating machine.

In particular, when using a two-liquid mixed type paint that requires strict flow rate control, etc., if pulsation occurs, the mixing ratio will change, and the curing speed and the cured state of the coating film will change. This will result in poor painting.

[Object of the Invention]

Therefore, the present invention accurately controls the supply amount without directly measuring the flow rate of a coating material having high viscosity or other coating agents,
An object of the present invention is to provide a coating agent supply device that can continuously supply the coating agent to a coating machine without causing pulsation while maintaining a predetermined flow rate set in advance.

[Structure of Invention]

In order to achieve this object, the present invention is a coating agent supply device for continuously supplying a coating agent fed at a predetermined pressure from a coating agent feeding source to a coating machine at a constant flow rate, which is a working fluid supply. A set of reciprocating pumps that supplies a coating fluid to the applicator at a flow rate corresponding to the flow rate of the working fluid by pressing the piston or diaphragm with the working fluid supplied at a constant flow rate from each source, and the working fluid to each reciprocating pump. One reciprocating pump for supplying the working fluid and an on-off valve for supplying the coating agent at a predetermined timing so that the supply of the coating agent from the coating agent supply source to each of the reciprocating pumps is interrupted when being supplied. From one reciprocating pump to another reciprocating pump before the working fluid is stopped from being supplied to the other reciprocating pump. Characterized in that a on-off valve for supplying sequentially alternately condensate pump.

[Operation of the invention]

According to the present invention, a constant flow rate of working fluid is sequentially supplied to a set of reciprocating pumps that press the piston or diaphragm by the working fluid to feed the coating agent at a flow rate according to the flow rate of the working fluid to the applicator. Therefore, the coating agent is continuously discharged from each reciprocating pump while being maintained at a constant flow rate according to the flow rate of the working fluid. At this time, since the supply of the coating agent from the coating agent supply source to the reciprocating pump is blocked, the discharge amount of the reciprocating pump does not change under the influence of the feeding pressure of the coating agent.

Further, the working fluid is sequentially supplied to the pair of reciprocating pumps, and when the supply of the working fluid is switched from one reciprocating pump to another reciprocating pump, the supply of the working fluid to one reciprocating pump is stopped. Supply of the working fluid to the other reciprocating pump is started, the one reciprocating pump is still in an operating state when the other reciprocating pump is started, and when the one reciprocating pump is stopped. Since the other reciprocating pump is already in operation, the coating agent can be continuously supplied to the coating machine without causing pulsation.

In this case, the working fluid is simultaneously supplied to the two reciprocating pumps and the coating material is discharged at the same time from the start of the other reciprocating pump to the stop of the one reciprocating pump. However, since the working fluid is maintained at a constant flow rate and distributed to the two reciprocating pumps to be supplied, the total flow rate of the coating agent discharged from the two reciprocating pumps is discharged from one reciprocating pump. If so, the amount is the same and the flow rate of the coating agent is kept constant.

〔Example〕

Hereinafter, the present invention will be described based on specific examples shown in the drawings.

FIG. 1 is a flow sheet showing an example of the coating agent supply device according to the present invention.

1A and 1B in the figure are spray guns (applicators) for the paint supplied from the paint circulation system (coating material supply source) 2 at a predetermined pressure.
3, a paint chamber 5 and a hydraulic oil chamber 6 are formed adjacent to each other via a diaphragm 4, and the hydraulic oil (working fluid) supplied to the hydraulic oil chamber 6 causes the diaphragm 4 to move. When pressed, the same amount of paint as the hydraulic oil is discharged.

In addition, an inlet 7 is provided in the paint chamber 5 of the reciprocating pump 1A (1B).
And an outlet 8 are formed. The inlet 7 is connected to the paint circulation system 2 via an on / off valve 9A (9B) for switching the feeding / blocking of the paint, and the outlet 8 is an on / off valve 10A.
It is connected to the spray gun 3 via (10B).

Reference numeral 12 denotes a working oil supply source (working fluid supply source) for supplying working oil to the reciprocating pumps 1A and 1B at a constant flow rate, and the working fluid in the working fluid tank 13 is driven by, for example, a gear pump 15 driven by a motor 14. The hydraulic oil is supplied to the hydraulic oil chambers 6 and 6 via the on / off valves 16A and 16B, and the hydraulic oil discharged from the nominal hydraulic oil chambers 6 and 6 is returned to the hydraulic oil tank 13 via the on / off valves 17A and 17B. Has been made.

Reference numeral 18 is a flow rate control device that maintains the amount of hydraulic fluid supplied by the gear pump 15 at a preset constant flow rate, and measures the flow rate of hydraulic fluid discharged from the gear pump 15 to the input side thereof. With the flow sensor 19 connected,
An inverter 20 that controls the rotation speed of the motor 14 that drives the gear pump 15 is connected to the output side, compares the flow rate measured by the flow rate sensor 19 with a preset flow rate, and rotates the motor 14 according to the deviation. The flow rate of the hydraulic oil discharged from the gear pump 15 is controlled by increasing or decreasing the value to maintain a constant flow rate.

As the hydraulic oil, resin-based paint is used so that even if the diaphragm 4 is damaged and mixes with the paint, there is little trouble and the flow rate can be easily measured by the flow rate sensor 19. In this case, for example, dioctyl phthalate (C24H38O4) is used.

Reference numeral 21 is a relief valve for returning the hydraulic oil to the tank 13 to prevent the gear pump 15 from being overloaded when the on / off valves 16A and 16B are closed. It is interlocked with (not shown) so that it is closed only when the trigger is pulled.

Reference numeral 22 is a back pressure valve for maintaining a constant pressure in the hydraulic oil supply pipe 23 regardless of whether the spray gun 3 is used or not used.

25 is an on-off valve 9A and 9B, 10A and 10B, 16 for alternately supplying hydraulic oil and paint to reciprocating pumps 1A and 1B.
An air control device for controlling opening / closing operations of A and 16B, 17A and 17B, which includes on / off valves 10A and 16A (10B
And 16B) are opened by the compressed air supplied from the air supply source 27A (27B) through the off-delay timer 26A (26B), and the on-off valves 9A and 17A (9B and 17B) are opened.
B) is opened by the compressed air supplied from the air supply source 29A (29B) via the on-delay timer 28A (28B).

An off-delay timer 26A (26B) for opening the on-off valves 10A and 16A (10B and 16B) is usually an air supply source.
Compressed air supplied from 27A (27B) is conducted, and when compressed air for signals is supplied from the air supply source 31 via the piston valve 30, air will be generated after a predetermined time (for example, 0.2 seconds). The compressed air supplied from the supply source 27A (27B) is shut off.

Further, the on-delay timer 28A (28B) that opens the on / off valves 9A and 17A (9B and 17B) normally shuts off the compressed air supplied from the air supply source 29A (29B), and the signal compression When the air is supplied, the compressed air supplied from the air supply source 29A (29B) is conducted after a lapse of a predetermined time (for example, 0.4 seconds).

32A and 32B are compressed air supply sources for signals for operating the on-delay timers 28A and 28B and switching the piston valve 30, and are rods fixed to the diaphragms 4 and 4 of the reciprocating pumps 1A and 1B. The on-delay timer is provided via piston valves 34A and 34B and AND gates 35A and 35B which are switched by 33A and 33B.
28A and 28B are supplied to the piston valve 30.

The AND gate 35A (35B) receives the compressed air from both the air supply sources 32A and 32B and outputs the compressed air to the timer 28.
It is output to A (28B), and after a lapse of a predetermined time, the timer 28A (28B
B) is made conductive and the piston valve 30 is switched.

The air supply sources 27A and 27B are interlocked with a trigger (not shown) of the spray gun 3 so that compressed air is output only when the trigger is triggered.
Compressed air is output to A and 29B, 31, 32A and 32B while the air control device 25 is turned on regardless of the trigger of the spray gun 3.

Further, in the paint circulation system 2, 36 is a paint tank, 37 is a paint feed pump that feeds the paint in the paint tank 36 at a predetermined pressure, and 38 is a reciprocating pump 1A and 1B by adjusting the paint feed pressure. This is a back pressure valve that regulates the feeding speed of the paint.

The above is an example configuration of the present invention, and its operation will be described below with reference to the time chart shown in FIG. Figure 2 (a) shows the pump with the on / off valves 10A and 16A opened.
1A shows a state where the paint is being discharged, (b) shows a state where the on / off valves 10B and 16B are opened and the pump 1B is discharging the paint, and (C) shows an on-off valve 9A and 17A.
Is opened and paint is being sent to pump 1A,
(D) Pump 1 with on / off valves 9B and 17B opened
The state where the paint is being sent to B is shown.

First, the flow control device 18 of the hydraulic oil supply source 12 sets a desired paint flow rate to drive the gear pump 15, and turns on the air control device 25 (T1 in FIG. 2).

At this time, the on / off valves 16A and 16B are still in the closed state, and therefore the hydraulic oil is released to the relief valve 21 and the back pressure valve.
It is returned to the hydraulic oil tank 13 through 22.

Further, when the air control device 25 is turned on, for example, the reciprocating pump 1A is filled with the coating material, the coating material of the reciprocating pump 1B is discharged, and the piston valves 34A and 34B are at the positions shown in FIG. Then, since the compressed air from the air supply sources 32A and 32B is input to the AND gate 35B, it is output from the AND gate 35B to the on-delay timer 28B and the piston valve 30, and is supplied from the air supply source 29B through the timer 28B. The compressed air is used to open the on / off valves 9B and 17B after a lapse of a predetermined time (0.4 seconds) (T in FIG. 2).
2). Therefore, the paint is supplied from the paint circulation system 2 to the paint chamber 5 of the reciprocating pump 1B, and the hydraulic oil is discharged from the hydraulic oil chamber 6 and recirculated to the tank 13.

Then, the paint is filled and the diaphragm 4 expands toward the hydraulic oil chamber 6 side, the rod 33B moves leftward in FIG. 1, and when the piston valve 34B is switched, the air is supplied from the air supply source 32B to the AND gate 35B. Compressed air is ANDGATE 35A
Therefore, the air supply from the AND gate 35B to the timer 28B is stopped, the timer 28B is shut off, and the on / off valves 9B and 17B are closed (T3 in FIG. 2).

Here, when a trigger (not shown) of the spray gun 3 is pulled, compressed air is output from the air supply sources 27A and 27B, the on / off valves 10A and 16A are opened, and the paint is discharged from the spray gun 3 (first (Fig. T4).

That is, at this point, the piston valve from the air supply source 31
Since compressed air is supplied to the timer 26B via 30, the timer 26B is in the cutoff state and the timer 26A is in the conduction state.

Therefore, the on / off valves 10A and 16A are opened by the compressed air supplied from the air supply source 27A through the timer 26A, and the working oil is reciprocated by the piston valve 16A.
It is supplied to the hydraulic oil chamber 6 of A, the diaphragm 4 is pressed by the hydraulic oil, and the same amount of paint as the flow rate of the hydraulic oil is supplied to the spray gun 3 through the on / off valve 10A. At this time, since the hydraulic oil is maintained at a constant flow rate by the flow rate control device 18, the paint discharged from the reciprocating pump 1A is also maintained at a constant flow rate.

Then, when the paint of the reciprocating pump 1A is discharged and the piston valve 34A is switched by the rod 33A, compressed air is output from the AND gate 35A to start the timer 28A, the piston valve 30 is switched, and the air supply source 31 is used. Compressed air that was being supplied to timer 26B is now replaced by timer 26A
(T5 in Fig. 2).

Therefore, the timer 26A, which has been in a conductive state until now, has a predetermined time (0.2
(Seconds), it will be shut off after 10 seconds.
6A is closed and the discharge of paint from the reciprocating pump 1A is stopped (T6 in FIG. 2).

On the other hand, when the piston valve 30 is switched, the supply of compressed air to the tile 26B is stopped, so that the timer 26B, which has been cut off until now, is turned on, and the on / off valves 10A and 16A are turned on.
Before the valve is closed, the on / off valves 10B and 16B are opened to supply the working oil to the reciprocating pump 1B (T5 in FIG. 2).

That is, until the on / off valves 10A and 16A are closed, both the on / off valves 10B and 16B are opened, but the flow rate of the hydraulic oil supplied from the hydraulic oil supply source 12 is maintained constant. Therefore, the total sum of the flow rates of the paints discharged from the reciprocating pumps 1A and 1B is kept constant, and therefore, the paint is continuously supplied from the reciprocating pumps 1A to 1B without causing the pulsation of the paint. Become.

Also, when the piston valve 34A switches, the timer 2
8A is activated, and after a lapse of a predetermined time (0.4 seconds), it becomes conductive and the on / off valves 9A and 17A are opened, and the paint is fed from the paint circulation system 2 to the reciprocating pump 1A at a predetermined pressure (T7 in FIG. 2). ).

When the paint chamber 5 of the reciprocating pump 1A is filled with the paint, the piston valve 34A is switched by the rod 33A fixed to the diaphragm 4, the output from the AND gate 35A is stopped, and the on / off valves 9A and 17A are turned on. It will be closed (Fig. 2, T8).

Next, when the paint of the reciprocating pump 1B is discharged and the piston valve 34B is switched by the rod 33B, compressed air is output from the AND gate 35B and the timer 28B is started, and the piston valve 30 is switched, and the air supply source is supplied.
The compressed air supplied from 31 to the timer 26A is again supplied to the timer 26B (T9 in FIG. 2).

Therefore, the timer 26B that has been conducting until now is the predetermined time (0.2 seconds) after the piston valve 34B is switched.
After a lapse of time, the valves are shut off, the on / off valves 10B and 16B are closed, and the discharge of the paint from the reciprocating pump 1B is stopped (T10 in FIG. 2).

On the other hand, when the piston valve 30 is switched, the supply of compressed air to the timer 26A is stopped, so that the timer 26A, which has been cut off until now, becomes conductive, and the on / off valves 10B and 16B are turned on.
Before the valve is closed, the on / off valves 10A and 16A are opened and the hydraulic oil is supplied to the reciprocating pump 1A again (T9 in FIG. 2).

Also, when the piston valve 34B is switched, the timer 2
8B is activated, and after a lapse of a predetermined time (0.4 seconds), it becomes conductive and the on / off valves 9B and 17B are opened, and the paint is circulated from the paint circulation system 2 to the reciprocating pump 1B at a predetermined pressure (Fig. 2, T11). After that, the reciprocating pumps 1A and 1B can be alternately switched in the same manner to continuously supply the paint to the spray gun 3.

Thus, according to the present invention, the on / off valves 10A and 16A are
While (10B and 16B) is opened and paint is being supplied to the spray gun 3, on / off valves 9A and 17A (9B and 1A)
7B) is always closed, the flow rate of the paint discharged from the reciprocating pump 1A (1B) is supplied from the working fluid supply source 12 without being affected by the paint sent from the paint circulation system 2. Determined only by the flow rate of hydraulic oil, the hydraulic oil is reciprocating pump 1A (1B) at a constant flow rate by the flow control device 18.
Therefore, the paint is supplied to the spray gun 3 at a constant flow rate.

Also, hydraulic oil is alternately supplied to the reciprocating pumps 1A and 1B,
When switching from reciprocating pump 1A to 1B (1B to 1A),
The supply of hydraulic oil to pump 1B (1A) is started before the supply of hydraulic oil to pump 1A (1B) is stopped, and reciprocating pump 1B is started when reciprocating pump 1A is in the operating state. When 1A stops, the reciprocating pump 1B is already in the operating state, so the coating agent is continuously discharged without pulsation.

In the description of the embodiments, a diaphragm is used as the reciprocating pump, but the present invention is not limited to this, and a piston pump, a plunger pump, etc. using a bellows may be used.

Further, in the embodiment, the case where the same amount of the coating material as the hydraulic oil is discharged has been described, but, for example, a piston pump is used as the reciprocating pump, cylinders are arranged at both end sides of the piston rod, and one cylinder is provided. When hydraulic oil is supplied and paint is discharged from the other cylinder, if the cross-sectional area of both cylinders is set to a predetermined ratio, the paint can be discharged at a predetermined flow rate proportional to the flow rate of hydraulic oil. .

Further, the case where two reciprocating pumps 1A and 1B are used as one set of reciprocating pumps has been described, but the present invention is not limited to this, and for example, working fluid is sequentially and alternately supplied to three or more reciprocating pumps. It may be the one that has been done.

Further, the working fluid is not limited to the above-mentioned dioctyl phthalate, it is possible to use other solvents or oil of low viscosity, when using a water-soluble paint as the coating agent, when using water as the working fluid. It may be.

Furthermore, the present invention is not limited to the case where a resin-based paint is supplied as a coating agent, and a coating agent supply device for supplying a water-soluble paint, an oil coating agent, an ink, a dye, a slurry liquid, a main component of a two-component mixed type paint, a curing agent, and the like. Can also be applied. In particular, when it is desired to supply the main component and the curing agent of the two-component mixed paint, the supply devices for the main component and the curing agent are installed side by side, and the supplied main component and the curing agent are mixed by the mixer, and then the spray gun 3 Should be supplied to.

As described above, according to the present invention, there is provided a set of reciprocating pumps which presses the piston or the diaphragm by the working fluid and supplies the coating agent at a flow rate corresponding to the flow rate of the working fluid to the coating machine. Since a constant flow rate of working fluid is alternately supplied, the coating agent is discharged from each reciprocating pump while being maintained at a constant flow rate according to the flow rate of the working fluid, and coating is performed without measuring the flow rate of the coating agent. There is an effect that it can be supplied to the machine at a constant flow rate.

Further, at this time, since the feeding of the coating agent from the coating agent feeding source to the reciprocating pump is cut off, it is not affected by the feeding pressure of the coating agent.

Further, the working fluid is alternately supplied to the pair of reciprocating pumps, and when the supply of the working fluid is switched from one reciprocating pump to another reciprocating pump, the supply of the working fluid to one reciprocating pump is stopped. Since the supply of the working fluid to the other reciprocating pump is started before the other reciprocating pump is started, the one reciprocating pump is still in an operating state,
Further, when the one pump is stopped, the other reciprocating pumps are already in the operating state, so that no pulsation occurs.

In this case, the working fluid is simultaneously supplied to the two reciprocating pumps and the coating agent is simultaneously discharged from the two reciprocating pumps from the time the other pumps are started until the one pump is stopped. However, since the working fluid is maintained at a constant flow rate and distributed and supplied to the two reciprocating pumps, the total flow rate of the coating agent discharged from the two reciprocating pumps is one reciprocating pump. The amount is the same as that when the reciprocating pump is switched, and therefore, there is an excellent effect that the coating agent can be continuously supplied to the coating machine without causing any pulsation even when the reciprocating pump is switched.

[Brief description of drawings]

FIG. 1 is a flow sheet showing one embodiment of the coating agent supply device according to the present invention, and FIG. 2 is a time chart showing the open / close state of the on / off valve. Explanation of symbols 1A, 1B ... Reciprocating pump, 2 ... Paint circulation system (coating agent supply source), 3 ... Spray gun (coating machine), 9A, 9B, 10A, 10B
...... On-off valve, 12 ...... Operating oil supply source (working fluid supply source), 15 ...... Gear pump, 16A, 16B, 17A, 17B ...... On-off valve, 18 ...... Flow control device, 19 ...... Flow sensor,
25 ... Air control device, 26A, 26B ... Off-delay timer, 28A, 28B ... On-delay timer, 30, 34A, 34B ... Piston valve, 35A, 35B ... AND gate.

Claims (2)

[Claims] 1. A coating fluid supply device for continuously feeding a coating fluid fed at a predetermined pressure from a coating fluid feeding source (2) to a coating machine (3), which is a working fluid supply source. A piston or diaphragm (4) is pressed by a working fluid supplied from (12) at a constant flow rate, and a set of reciprocating pumps (a set of reciprocating pumps that supplies a coating agent at a flow rate corresponding to the flow rate of the working fluid to the coating machine (3) ( 1A, 1B) and each reciprocating pump (1A, 1B) from the coating agent supply source (2) when the working fluid is supplied to each reciprocating pump (1A, 1B)
ON / OFF valve (9A or 9B) that supplies the coating agent at a predetermined timing so that the supply of the coating agent to the unit is cut off, and the supply of working fluid from one reciprocating pump (1A or 1B) to another reciprocating pump (1B or 1A), the supply of the working fluid to the other reciprocating pump (1B or 1A) is started before the supply of the working fluid to the one reciprocating pump (1A or 1B) is stopped. As described above, an application agent supply device comprising an on-off valve (16B or 16A) for sequentially and alternately supplying a working fluid to each reciprocating pump (1A, 1B) at a predetermined timing. 2. The coating agent supply device according to claim 1, wherein the working fluid is dioctyl phthalate.